Machine for forming tubes of soft metal.



' PATBNTED JULY 7, 190s.

W. s. CLARK. MAGHINL TOR TORMTNG TUBES 0T soTT METAL.

APPLIOATION ILED TLB. E 1991.

N0 MODEL.

UNITED` STATES l Patented July 7', 1903.

PATENT OFFICE.

WALLACE S. CLARK, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

MACHINE FOR FORMING TUBES F sol-"r METAL.

SPECIFICATION forming part of Letters Patent N o. 732,829, datedJuly 7,1903. Application filed February 8, 1901, Serial No. 46,500. iNo model.)

To @ZZ whom it may concern.: u Be it known that I, WALLACE S. CLARK, acitizen of the United States, residing at Schenectady, countyofSchenectady, State of N ew i York, have invented certain new anduseful Improvements in Machines for Forming Tubes of Soft Metal, ofwhich the following is a specification.

This invention relates to machines for forming a continuous seamlesstube of soft metal, such as lead or an alloy of lead and tin or anyother suitable plastic or semiplastic material,

`such as gutta-percha, india-rubber and its compounds, tar or asphaltcompounds, or the like. One use to which such machines are put iscovering electric conductors or cables with a sheath of the desiredmaterial. mode of operation consistsin leading the conductoror cablethrough a tubular mandrel which passes into a receptacle for the lead orother material and terminates adjacentto a die, leavingian annularspace, through which the plastic material is forced in the shape of atube closely surrounding the conductor.`

This process requires that rthe mandrel shall remain at all timesexactly concentricwith the die in order that the thickness of the sheathor covering maybe uniform.

In the machine embodying my improvements the mandrel and the receptacleforthe plastic material are supported on a verticallymovable piston orram, by means of which they can be raised, so that astationary annularplunger concentric with the mandrel- Acan enterthe receptacle and forcethe plastic material through the die at the bottom as the receptaclerises. i I provide the pedestal on' which the receptacle rests with acentral chamber'open on one side, so that the incased conductor comingdown through the die can be led oft' to one side and reeled up.

In the following description I havefor the sake of convenience assumedthat the material to be operated on is lead; but it should beclearlyunderstood that I do not thereby intend to limit the use of my machineto any given material.

In the accompanying drawings, Figure l is a top plan view of my improvedpress. Fig. 2 is a vertical section thereof on the line 2 2, Fig. l.Fig. 3 is an enlargement of that por- The y above the packing E.

tion of Fig. 2 showing the die at the bottom of the lead-receptacle.Fig. 4 is an enlarged vertical section of the lower end of the mandrel.Fig. 5 is an enlarged detail sectional view of a portion of the ram andits packing. Fig. 6 is a cross-section of Fig. 2 on the line 6 6 on anenlarged scale.

The frame of the machine comprises stout pillars or standards A,preferably three in ,number and placed at the angles of .an equilateraltriangle. At a given height above their lower ends the standards supporta heavy rigid bed-plate B. This is preferably clamped against collars aon the standards by nuts Ai engaging with screw-threads a' cut in thestandards. The upper ends of the standards are united by a heavy rigidcapplate C, which is adjustable vertically by means of nuts A2 engagingscrew-threads 'a2 on the standards above and below said capplate. Thebed-plate has a central opening to receive the cylinder D, whichpreferably hangs suspended by a flange d, resting onv thehed-plate, andhas abrass or similar lining d'. In the lower end ofthe cylinder is apacked pipe connection D', by means of which fluid-pressure can beconveyed to the cylinder and raise a piston-ram E therein, preferably atubular structure having a jacket e, of brass or the like, and providedat its lower end with a packing-diskE,of leather or the likecupped tomake a fluid-tight joint and clamped in place by a-plate E2, held byscrews e. An annular packing E3 surrounds the ram just At the upper endof the cylinder is an annular semicylindrical Vpacking D2, retained in acountersink in the cylinder by a ring D3 and an annular gland D4,secured to the top of the cylinder and closely fitting the ram. A pipe Fenters the annular space between the ram and the cylinder just below thepacking D2.4 V

Resting on the top of the ram andfirmly attached thereto is a pedestalor space-block G, preferably iiuted vertically to give it strength withcomparative lightness and containing a central chamber g open on oneside, as shown in Fig. 6. The top of the pedestal has a central openingthrough it, which is counterbored to form a seat for the annulardie-block I-I, having a tubular central neck 7i passingdown IOO throughthe opening in the pedestal and therel in secured, as by a nut h',screwed upon the neck and abutting against the under side of thepedestal top, as shown in Fig. 3. The dieblock has some lateral play onits seat and can be adjusted by means of set-screws G', passingtransversely through the upper part of the pedestal and abutting againstthe die-block.

In the tubular neck h is screwed a bushing H', on which rests an annularbolster` H2, having an inwardly-beveled upper edge and an internalflange h2, on which rests the die I, consisting of a ring having abeveled upper edge in line with the beveled edge of the bolster H2. 'Iheopening through the die is slightly smaller than that through thebolster and bushing to give plenty of clearance for the incasedconductor leaving the die.

The die-block H forms the bottom of the lead-receptacle K, which has acylindrical interior and is strengthened by a series of heavy hoops k,the lower one having ears 7c' to receive the bolts K', by which it isfastened to the pedestal G. Upright guide-rods L are inserted into theupper hoops and rise through holes in the cap-plate, their upper endsbeing rigidly connected by a yoke M, adjustably secured to the rods bynuts m. The holes in the cap-plate are preferably a little larger thanthe rods, which are accurately guided by plates N, secured to thecap-plate and having holes engaging the rods with a sliding t. A tubularmandrel P is adj ustably secured by nuts p in a hole at the center ofthe yoke and passes centrally through a passage-way in the cap-plate,terminating just above the die I, the axis of the mandrel beingcoincident with that of the die. The nuts p provide for the adjustmentof the annular space between the die and the end of the mandrel.

Astationary plungerR is secured to the underside of the cap-plate,preferably by means of a flanged collar R', engaging a .flange fron theplunger and having ears r' to receive the bolts R2, which are preferablyhinged to the cap-plate, as shown in Fig. 2. The plunger is tubular toallow the mandrel to pass through it, having bushings z2 screwed intoits ends and fitting the mandrel snugly, so as to center the mandrelaccurately. The plunger lits the cylindrical interior of thelead-receptacle, so that it will enter it and expel the lead when thereceptacle is lifted by the ram.

In orderto insure a uniform thickness of the tube or sheath, the end ofthe mandrel is so made as to have a swiveling or universal joint action,so that the pressure of the lead will hold it concentric with the dieand will automatically center it if accidentally displaced. Thepreferred construction is shown in Fig. 4t, wherein the nozzle P' has areduced portion p' provided with a flange p2 and fitting into a socketin the end of the mandrel, where it is secured by a bushing P2, screwedinto the'socket. The shoulder p2 and the upper end of the nozzle and thecorresponding faces of the nut and mandrel are curved on the arcs ofconcentric spheres, so that the nozzle has a universal ball-jointaction. The tip p3 of the nozzle is removable, in order to allow it tobe changed or renewed at pleasure. By properly shaping the outside ofthe nozzle and tip the downward pull on them, due to the friction of thelead flowing over their surfaces, may be made to balance the upwardthrust due to the pressure exerted on all surfaces within the cylinder.As the pressure in the annular space between the nozzle and the die isgreatest at the point where the metal is thinnest, the result is to pushthe nozzle over toward that side of the die where the metal is thickest,thereby equalizin g the thickness of the metal and evening up thepressure. The frictional resistance to motion through the die and coretube or mandrel where the space is narrowest producesa greater relativeinterference with the motion of the metal at that place than where it iswider, causing pressure to be stored or a greater back pressure to beproduced at that point than where the space is wider. This results inswinging the movable core-tube laterally and equalizing the space.

The operation of the press when making a tube or applying a sheath to acable is as follows: The receptacle is filled with molten lead, which isallowed to cool sufficiently to solidify. The ram is then raised byfluidpressure, carrying the receptacle up over the stationary plungerand forcing the lead to escape between the nozzle and the die in theshape of a seamless tube. If a cable is to be covered, it is fed downthrough the mandrel at the same rate of speed as the formation of thepipe. The lead will continue to flow out at the bottom of the receptacleuntil the limit of movement of the ram is reached. This is so adjustedthat a residue of lead of suitable thickness-say three inches-remains inthe bottom of the receptacle. The fluid-pressure is then cut off fromthe pipe D' at the bottom of the cylinder and a suitable port or cockopened and pressure admitted through thev pipe F, each pipe D' and Facting as a supply and exhaust pipe, forcing the ram downward and withit the pedestal, receptacle, mandrel, guide-rods, and yoke until the topof the receptacle is below the plunger. A fresh charge of molten lead isthen run into the receptacle, where it unites with the residue of theformer charge, and when it has solidilied the press is ready to form afurther length of pipe. of steps can be repeated indefinitely, so that apipe or sheath of any length can be produced. The iinished product 'isguided off laterally through the open side of the chamber g.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is-

l. The combination with a ram and a pedestal thereon, of a plunger, adie-block mounted on the pedestal, a bushing screwed into saiddie-block, a anged bolster supported Itis evident that this cyclev IIOon said bushing, and a die resting on said bolster.

2. The combination of a downwardly-projecting mandrel, a self-adjustingnozzle secured thereto and independently laterally movable in anyhorizontal direction under irregularities of lead-pressure, and a diebe# neath the nozzle.

3. In a 1eadpress, the combination with a receptacle, of avertically-adjustable',die in its bottom, and a vertically-adjustablemandrel terminating just above said die, said mandrel having a self-adjusting laterallymovable nozzle. Y

4. In a lead-press, the combination with a tubular mandrel, of a nozzletherefor, and a bushing for securing it to the mandrel, the

\ meeting faces of the nozzle and bushing being on the arc of a sphere.A

5. In a lead-press, the combination with a Vtubular mandrel having asocket in its end,

of a nozzle provided with a reducedportion to enter said socket, andhaving a flange at its upper end, and a bushing to screw into the socketand abut against said iiange, the

meeting faces of the socket, nozzle and bush- Y ing, being on arcs ot'spheres.

6. In a lead-press, the combination with a receptacle, of a die, and astationary mandrel provided with a self-adj usting laterally-movablenozzle having such a tapered surface that the friction of the leadthereon balances the tendency of the pressure to separate the die andmandrel.

In witness whereof I have hereunto set my 3 5 hand this 6th day ofFebruary, 1901.

WALLACE S. CLARK. Witnesses:

BENJAMIN B. HULL, MARGARET E. WooLLEY.

